In the first study of expandable cages, prospective data from 43 consecutive adults who underwent posterior fusion with TLIF for deformity was divided into similar groups by type of TLIF cage used: expandable vs static height. Though numbers were small, expandable cage group consistently trended toward better disc height, segmental lordosis, lumbar lordosis, and sagittal balance compared to the static height cage group. There was no difference in clinical outcomes at 4 years followup. These preliminary observations warrant further study.